Method for calculating continuous Young's modulus of core

Abstract

The present invention provides a method for calculating the continuous Young's modulus of a core, including determining first data of the scratch modulus of the core varying with the core depth, sampling a plurality of calibration samples in sequence along the core depth direction, selecting data corresponding to each calibration sample in the first data as the calibration scratch modulus, and determining the calibration Young's modulus of each calibration sample by experiment, determining the functional relationship between the calibration scratch modulus and the calibration Young's modulus, and determining the continuous Young's modulus data of the core varying with the core depth according to the functional relationship and the first data. Each calibration sample can represent one of the local positions of the core, and the continuous Young's modulus data of the core is determined by finding the corresponding relationship between the scratch modulus and the Young's modulus at the local position of the core. The continuous Young's modulus data of the core includes the Young's modulus data of each core depth, so that the mechanical properties of the entire core can be fully characterized.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum engineering, and in particular relates to a method for calculating the continuous Young's modulus of a core. Background Art

[0002] In the petroleum engineering industry, the Young's modulus of rock is a physical quantity that describes the rock's ability to resist deformation. In the core analysis experiment of the petroleum geology industry, according to Hooke's law, the core is usually subjected to a single triaxial compression test, and the stress-strain curve of the core is obtained through the experiment. The ratio of stress to strain within the elastic limit of the core is taken as the Young's modulus of the core. The single triaxial compression test in the laboratory has high requirements on the size of the experimental rock sample, and usually can only reflect the overall properties of the experimental rock sample. For unconventional oil and gas reservoirs, such as shale reservoirs, their geological heterogeneity and anisotropy are very obvious, and the composition and microstructure of the rock may change significantly in the range of centimeters to millimeters in the core depth direction. Therefore, it is difficult to accurately characterize the core mechanical properties of such unconventional reservoirs based solely on the measurement results of the single triaxial compression test. Summary of the invention

[0003] In view of the above-mentioned defects or shortcomings, the present invention provides a method for calculating the continuous Young's modulus of the core, aiming to solve the technical problem that the existing method for calculating Young's modulus is difficult to accurately characterize the mechanical properties of the core of unconventional oil and gas reservoirs.

[0004] To achieve the above object, the present invention provides a method for calculating the continuous Young's modulus of a core, wherein the method for calculating the continuous Young's modulus of a core comprises:

[0005] Using a tool to perform a scratch test on the core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth;

[0006] A plurality of calibration samples are sequentially sampled from the core along the core depth direction, and a calibration scratch modulus of each calibration sample is determined according to the core depth of each calibration sample, the sampling position of each calibration sample in the core, and the first data, and at the same time, each calibration sample is experimentally determined to determine a calibration Young's modulus of each calibration sample;

[0007] The functional relationship between the calibrated scratch modulus and the calibrated Young's modulus is determined according to the calibrated scratch modulus and the calibrated Young's modulus, and the core continuous Young's modulus data of the core changing with the core depth is determined according to the functional relationship and the first data.

[0008] In an embodiment of the present invention, the step of using a tool to perform a scratch test experiment on a core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth includes:

[0009] The core is scratched using a tool along the core depth direction to determine the original output data of the tool's tangential force varying with the core depth;

[0010] Perform slope calculation on the original output data to determine the intermediate processed data of slope value varying with core depth;

[0011] The intermediate processed data are screened and calculated to determine the first data of the scratch modulus of the core changing with the core depth.

[0012] In an embodiment of the present invention, the steps of using a tool to perform a scratch test on a core along the core depth direction to determine the original output data of the tool's tangential force varying with the core depth include:

[0013] Clamp and fix the core;

[0014] The tool starts to scrape the core from the core surface position along the core depth direction. Each time the scraping tool is moved vertically to a predetermined cutting depth, and each time the scraping angle and scraping speed of the tool are the same;

[0015] Record the tangential force variation data of the tool during the scraping process as the tangential force changes with the core depth;

[0016] Select appropriate data from the tangential force change data as the original output data.

[0017] In an embodiment of the present invention, the steps of calculating the slope of the original output data and determining the intermediate processed data of the slope value varying with the core depth include:

[0018] Dividing the original output data into multiple segments of unit original output data;

[0019] The slope of each unit's original output data is calculated to determine the intermediate processing data;

[0020] The slope value calculation formula is:

[0021] ;

[0022] is the slope value of the original output data of the i-th unit, in N / m; y B , y A is the first and last ordinate values ​​of the original output data of the i-th unit, in units of N. S i It is the length of the core depth corresponding to the original output data of the i-th unit, in meters.

[0023] In an embodiment of the present invention, the step of screening and calculating the intermediate processing data to determine the first data of the scratch modulus of the core varying with the core depth includes:

[0024] Filter out the slopes with a slope greater than 0 in the intermediate processing data as valid slopes;

[0025] According to the effective slope, tool width and cutting depth, the corresponding relationship between the scratch modulus corresponding to each effective slope and the core depth is determined according to the scratch modulus calculation formula;

[0026] The first data of the variation of the scratch modulus of the core with the core depth is determined according to the corresponding relationship between the scratch modulus corresponding to the effective slope and the core depth.

[0027] In an embodiment of the present invention, the scratch modulus calculation formula is:

[0028] ;

[0029] in, is the scratch modulus, in units of ; w is the tool width, in meters; d is the cutting depth, in meters; is the slope.

[0030] In an embodiment of the present invention, the step of determining the calibration scratch modulus of each calibration sample according to the core depth on each calibration sample, the sampling position of each calibration sample on the core and the first data comprises:

[0031] According to the core depth of the calibration sample and the sampling position of the calibration sample in the core, a corresponding part of the data is selected from the first data as a sample scratch modulus data set;

[0032] Calculate the mean of all scratch modulus data in the sample scratch modulus data set to determine the calibrated scratch modulus;

[0033] The mean calculation formula is:

[0034] ;

[0035] in is the sum of all scratch modulus data in the sample scratch modulus data set corresponding to the i-th calibration sample, in units of ; Q—the number of scratch modulus data in the sample scratch modulus data set, dimensionless, is the calibrated scratch modulus of the ith calibration sample, in units of .

[0036] In an embodiment of the present invention, the method of conducting experiments on calibration samples to determine the calibration Young's modulus data of each calibration sample is a uniaxial triaxial compression test method.

[0037] In an embodiment of the present invention, the step of determining the functional relationship between the calibrated scratch modulus and the calibrated Young's modulus comprises:

[0038] A coordinate system is introduced, with the calibrated scratch modulus as the abscissa and the calibrated Young's modulus as the ordinate, and a linear fitting method is used to determine the linear function relationship between the calibrated Young's modulus and the calibrated scratch modulus.

[0039] In an embodiment of the present invention, the step of determining the core continuous Young's modulus data of the core according to the functional relationship and the first data, wherein the Young's modulus of the core varies with the core depth, comprises:

[0040] Get the slope of a linear function relationship;

[0041] According to the length of the core depth, a suitable segmentation coefficient is selected to evenly segment the first data to obtain multiple segmented data, and the corresponding relationship between the mean value of the scratch modulus in each segmented data and the core depth is determined;

[0042] Determine the corresponding relationship data of the core Young's modulus and the core depth of each segmented data according to the corresponding relationship between the mean value of the scratch modulus and the core depth in each segmented data and the slope of the linear function relationship;

[0043] The core continuous Young's modulus data is determined based on the corresponding relationship data between the core Young's modulus and the core depth of all segmented data.

[0044] Through the above technical solution, the method for calculating the continuous Young's modulus of the core provided by the embodiment of the present invention has the following beneficial effects:

[0045] The method for calculating the continuous Young's modulus of the core provided by the present invention obtains first data of the scratch modulus of the entire core varying with the core depth by performing a scratch test experiment on the core, then sequentially samples a plurality of calibration samples from the core, performs experiments on the calibration samples to obtain the calibrated Young's modulus of each calibration sample, and selects data corresponding to the calibration sample in the first data according to the length and sampling position of the calibration sample, and calculates the data of these corresponding parts according to a preset method, thereby determining the calibrated scratch modulus of each sample, and by finding the corresponding relationship between the calibrated scratch modulus and the calibrated Young's modulus of each calibration sample, the core continuous Young's modulus data of the entire core can be determined. In summary, in the method for calculating the continuous Young's modulus of the core provided by the present invention, the calibrated scratch modulus and calibrated Young's modulus of each calibration sample can represent the scratch modulus and Young's modulus at a local position of the core. The corresponding relationship between the scratch modulus and the Young's modulus at the local position of the core is found, thereby determining the continuous Young's modulus data of the core. Since the continuous Young's modulus data of the core contains the Young's modulus data of the core corresponding to each core depth, it can fully characterize the mechanical properties of the entire core.

[0046] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide an understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0048] Figure 1 is a flowchart of the steps of a method for calculating the continuous Young's modulus of a core according to an embodiment of the present invention;

[0049] Figure 2 is a specific step diagram of step S10 in an embodiment of the present invention;

[0050] Figure 3 is a specific step diagram of step S110 in an embodiment of the present invention;

[0051] Figure 4 is a specific step diagram of step S120 in an embodiment of the present invention;

[0052] Figure 5 is a specific step diagram of step S130 in an embodiment of the present invention;

[0053] Figure 6 is a specific step diagram of step S20 in an embodiment of the present invention;

[0054] Figure 7is a specific step diagram of step S30 in an embodiment of the present invention;

[0055] Figure 8 is a specific example of original output data according to an embodiment of the present invention;

[0056] Fig. 9 is a specific example of step S120 and step S130 according to the embodiment of the present invention;

[0057] Fig.10 is a specific example of calibrating the scratch modulus and calibrating the Young's modulus in step S30 in an embodiment of the present invention;

[0058] Fig.11 is a specific example of the corresponding relationship between the mean value of the scratch modulus in each segmented data and the core depth in step S302 according to the embodiment of the present invention;

[0059] Fig.12 It is a specific example of the continuous Young's modulus data of the core according to the embodiment of the present invention. DETAILED DESCRIPTION

[0060] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0061] The method for calculating the continuous Young's modulus of a core according to the present invention will be described below with reference to the accompanying drawings.

[0062] The present invention provides a method for calculating the continuous Young's modulus of a core, wherein, Figure 1 As shown, the method for calculating the continuous Young's modulus of the core includes:

[0063] S10: using a tool to perform a scratch test experiment on the core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth;

[0064] S20: sampling a plurality of calibration samples in sequence from the core along the core depth direction, determining a calibration scratch modulus of each calibration sample according to the core depth of each calibration sample, a sampling position of each calibration sample in the core and the first data, and performing an experiment on each calibration sample to determine a calibration Young's modulus of each calibration sample;

[0065] S30: determining a functional relationship between the calibrated scratch modulus and the calibrated Young's modulus according to the two, and determining core continuous Young's modulus data of the core in which the Young's modulus of the core changes with the core depth according to the functional relationship and the first data.

[0066] The method for calculating the continuous Young's modulus of the core provided by the present invention obtains first data of the scratch modulus of the entire core varying with the core depth by performing a scratch test experiment on the core, then sequentially samples a plurality of calibration samples from the core, performs experiments on the calibration samples to obtain the calibrated Young's modulus of each calibration sample, and selects data corresponding to the calibration sample in the first data according to the length and sampling position of the calibration sample, and calculates the data of these corresponding parts according to a preset method, thereby determining the calibrated scratch modulus of each sample, and by finding the corresponding relationship between the calibrated scratch modulus and the calibrated Young's modulus of each calibration sample, the core continuous Young's modulus data of the entire core can be determined. In summary, in the method for calculating the continuous Young's modulus of the core provided by the present invention, the calibrated scratch modulus and calibrated Young's modulus of each calibration sample can represent the scratch modulus and Young's modulus at a local position of the core. The corresponding relationship between the scratch modulus and the Young's modulus at the local position of the core is found, thereby determining the continuous Young's modulus data of the core. Since the continuous Young's modulus data of the core contains the Young's modulus data of the core corresponding to each core depth, it can fully characterize the mechanical properties of the entire core.

[0067] Specifically, Figure 8 and Fig. 9 As shown, Figure 8 The Core Depth in is the core depth, F is the tangential force, Fig. 9 middle is the scratch modulus, s is the core depth, Ki is the slope, Figure 8 to Figure 9It indicates the process of obtaining the first data by calculating and processing the raw output data of the part. When performing the scratch test experiment, the tool starts from the surface of the rock and scratches the core along the depth direction of the core and leaves scratches, where the core depth refers to the depth of the core buried in the formation, and the core depth direction is the same as the depth direction of the formation when the core is in the formation. Take one of the specific data as an example. For example, if a cylindrical core is obtained from a formation position at a depth of 3833.0-3833.4 meters, the diameter of the core is 0.3 meters, and the length is 0.4 meters, then the core depth is 3833.0-3833.4 meters. A scratch test experiment is performed on the surface of the core along the depth direction of the core, and the first data of the scratch modulus of the core varying with the core depth at a core depth of 0.4 meters can be obtained. Then, 4 calibration samples of the same size are taken from the core at equal intervals along the core depth direction. The size of each calibration sample is assumed to be a small cylinder with a diameter of 2.5 cm and a length of 2 cm, and the length direction of the small cylinder is parallel to the core depth direction. The sampling positions of the four small cylinders are 0.05 meters from the end face of the rock sample, For the 0.15 meter, 0.25 meter and 0.35 meter, according to the length of the calibration sample and the sampling position, the core depth in the first data can be 3833.05-3833.07 meters, 3833.15-3833.17 meters, 3833.25-3833.27 meters, 3833.35-3833.37 meters, or 0.05-0.07, 0.15-0.17, 0.25-0.27, 0.35-0.37 meters of the core length, and the corresponding parts of the first data are respectively selected as the sample scratch modulus data set, and then these data are calculated and processed, so as to obtain the corresponding relationship data between the calibration scratch modulus and the core depth position of each calibration sample. The sampling positions of the calibration samples can be taken at different cross-sectional positions. For example, the first calibration sample is on the core surface, and the second calibration sample can be sampled inside the core at a certain distance from the core surface.

[0068] like Figure 2 , Figure 8 and Fig. 9 As shown, in an embodiment of the present invention, the step of using a tool to perform a scratch test experiment on a core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth includes:

[0069] S110: using a tool to perform a scratch test experiment on the core along the core depth direction to determine the original output data of the tool tangential force changing with the core depth;

[0070] S120: performing slope calculation on the original output data to determine intermediate processing data of the slope value varying with the core depth;

[0071] S130: Screening and calculating the intermediate processing data to determine first data of the scratch modulus of the core varying with the core depth.

[0072] Figure 8 An example of a cutout of the original output data is shown below. Fig. 9 It is a data change process from original output data to filtered intermediate processed data and then to first data, such as Figure 8 and Fig. 9 As shown in the figure, in the original output data, the curve of the tool's tangential force changing with the core depth fluctuates up and down in a sawtooth shape, and the tool scraping process in the scratch test experiment can be regarded as countless tiny uniaxial compression tests. Therefore, each positive peak of the curve in the original output data can be analogized to the linear elastic segment of the stress-strain curve of uniaxial compression, and the negative peak is equivalent to the rock having exceeded the elastic change limit, so the negative peak can be removed. In the existing uniaxial compression test, the formula for calculating Young's modulus is:

[0073] ;

[0074] Where, E—Young's modulus, MPa; —stress, MPa; —strain, %; Therefore, in the present invention, the slope corresponding to the positive peak value in the original output data represents the stress at the corresponding core scratch position, and then through corresponding calculation, the first data of the scratch modulus of the core changing with the core depth can be determined.

[0075] like Figure 3 As shown, in an embodiment of the present invention, the steps of using a tool to perform a scratch test on a core along the core depth direction to determine the original output data of the tangential force of the tool varying with the core depth include:

[0076] S111: clamp and fix the core;

[0077] S112: the tool starts to scrape the core from the core surface position along the direction of the core depth, and each time the scraping tool steps to a predetermined cutting depth in a direction perpendicular to the core depth direction, and each time the scraping angle and scraping speed of the tool are the same;

[0078] S113: recording the tangential force variation data of the tool during the scraping process as the tangential force varies with the core depth;

[0079] S114: Select appropriate data from the tangential force change data as original output data.

[0080] Specifically, after the core is clamped and fixed, the surface of the core is first leveled, that is, the tool first scrapes and leveled the surface of the core from one end of the core according to the predetermined cutting depth d (such as d=0.18mm), that is, after scraping once, the tool returns to the starting position, and based on the cutting depth of the last scraping, it continues to scrape and level by stepping the cutting depth d. After repeated leveling, the horizontality and smoothness of the scratches on the core can be guaranteed. After the leveling work is completed, continue to scrape multiple times according to the above leveling steps, and record the tangential force change data of the tool during each scraping as the core depth changes. Since the tool has a scraping angle during the scraping process, the tangential force of the tool is the component of the force received by the tool in the direction of tool movement. Selecting appropriate data from the tangential force change data as the original output data means selecting two or three groups of data with the same change trend from the multiple groups of data recorded above as the original output data, that is, after the core is leveled, the changes in the data recorded each time tend to be the same. Therefore, selecting the recorded data after leveling can avoid the influence of the uneven core surface on the experimental data, and selecting multiple groups of original output data for processing together can refer to each other in data processing, thereby ensuring the accuracy of the data.

[0081] like Figure 4 , Figure 8 and Fig. 9 As shown, in an embodiment of the present invention, the steps of calculating the slope of the original output data and determining the intermediate processed data of the slope value varying with the core depth include:

[0082] S121: Divide the original output data into multiple segments of unit original output data;

[0083] S122: performing slope calculation on each segment of the original output data of the unit to determine the intermediate processing data;

[0084] The slope value calculation formula is:

[0085] ;

[0086] K i is the slope value of the original output data of the i-th unit, in N / m; y B , y A is the first and last ordinate values ​​of the original output data of the i-th unit, in units of N. S i It is the length of the core depth corresponding to the original output data of the i-th unit, in meters.

[0087] Specifically, the curve of the tool's tangential force varying with the core depth in the original output data fluctuates up and down in a sawtooth shape. Each positive peak of the curve in the original output data can be analogized to the linear elastic segment of the stress-strain curve of uniaxial compression, while the negative peak is equivalent to the rock having exceeded the elastic change limit. The original output data is divided into multiple segments of unit original output data based on the positive and negative peaks, and then the slope of each segment of the unit original output data is calculated separately according to the slope calculation formula, and then it is matched with the core depth to determine the intermediate processed data.

[0088] like Figure 5 and Fig. 9 As shown, in an embodiment of the present invention, the steps of screening and calculating the intermediate processing data to determine the first data of the scratch modulus of the core varying with the core depth include:

[0089] S131: Filter out the slopes with slopes greater than 0 in the intermediate processing data as valid slopes;

[0090] S132: determining a corresponding relationship between a scratch modulus corresponding to each effective slope and a core depth according to a scratch modulus calculation formula according to the effective slope, tool width, and cutting depth;

[0091] S133: Determine first data of the variation of the scratch modulus of the core with the core depth according to the corresponding relationship between the scratch modulus corresponding to the effective slope and the core depth.

[0092] like Fig. 9 As shown, the slope of the positive peak in the original output data is greater than 0, and the slope of the negative peak is less than 0. Each positive peak of the curve in the original output data can be analogized to the linear elastic segment of the stress-strain curve of uniaxial compression, and the negative peak is equivalent to the rock having exceeded the elastic change limit. Therefore, the data of the negative peak can be discarded, and the slope corresponding to the positive peak is used as the effective slope. Then, according to the scratch modulus calculation formula, the calculated scratch modulus is matched with the core depth, so that the first data of the scratch modulus changing with the core depth can be obtained.

[0093] In an embodiment of the present invention, the scratch modulus calculation formula is:

[0094] ;

[0095] in, is the scratch modulus, in units of ; w is the tool width, in meters; d is the cutting depth, in meters; is the slope.

[0096] like Figure 6As shown, in an embodiment of the present invention, the step of determining the calibration scratch modulus of each calibration sample according to the core depth on each calibration sample, the sampling position of each calibration sample in the core and the first data includes:

[0097] S201: According to the core depth of the calibration sample and the sampling position of the calibration sample in the core, select the corresponding part of the data in the first data as the sample scratch modulus data set;

[0098] S202: Calculate the mean of all scratch modulus data in the sample scratch modulus data set to determine a calibrated scratch modulus;

[0099] The mean calculation formula is:

[0100] ;

[0101] in is the sum of all scratch modulus data in the sample scratch modulus data set corresponding to the i-th calibration sample, i=(1, 2, 3···), in units of ; Q is the number of scratch modulus data in the sample scratch modulus data set, dimensionless, is the calibrated scratch modulus of the ith calibration sample, in units of .

[0102] That is, the calibration scratch modulus is the average value of the sample scratch modulus data set. By calculating the mean, the calibration sample can more accurately reflect the local characteristics of the entire core and avoid occasional errors in the data. Of course, other methods can also be used to calculate the calibration scratch modulus, such as weighted average, mean square error, etc.

[0103] In an embodiment of the present invention, the method for conducting experiments on calibration samples to determine the calibration Young's modulus data of each calibration sample is a uniaxial triaxial compression test method. The uniaxial triaxial test refers to placing the calibration sample on a rigid pressure testing machine, and squeezing it in three directions to obtain the stress-strain curve of the calibration rock sample in the elastic stage, and then calculating the slope of the stress-strain curve to obtain the calibration Young's modulus. Since the calibration sample is smaller than the entire core, the calibration Young's modulus of the calibration sample can reflect the local Young's modulus of the corresponding position of the core.

[0104] like Fig.10 As shown, To calibrate the scratch modulus, To calibrate the Young's modulus, step (i) is the i-th calibration sample. In an embodiment of the present invention, the step of determining the functional relationship between the calibrated scratch modulus and the calibrated Young's modulus includes:

[0105] A coordinate system is introduced, with the calibrated scratch modulus as the horizontal coordinate and the calibrated Young's modulus as the vertical coordinate, and a linear fitting method is used to determine the linear function relationship between the calibrated Young's modulus and the calibrated scratch modulus. Linear fitting is relatively simple and intuitive, and of course other algorithms can also be used for fitting, such as quadratic fitting.

[0106] like Figure 7 , Fig.10 , Fig.11 and Fig.12 As shown, in an embodiment of the present invention, the step of determining the core continuous Young's modulus data of the core according to the functional relationship and the first data, in which the Young's modulus of the core varies with the core depth, comprises:

[0107] S301: Obtaining the slope of the linear function relationship;

[0108] S302: According to the length of the core depth, select a suitable segmentation coefficient to evenly segment the first data to obtain multiple segmented data, and determine the corresponding relationship between the mean value of the scratch modulus in each segmented data and the core depth;

[0109] S303: determining the corresponding relationship data of the core Young's modulus and the core depth of each segmented data according to the determined corresponding relationship between the mean value of the scratch modulus and the core depth in each segmented data and the slope of the linear function relationship;

[0110] S304: Determine core continuous Young's modulus data according to the corresponding relationship data between the core Young's modulus and the core depth of all segmented data.

[0111] Taking specific data as an example, corresponding to step S301, the slope of the linear function relationship is as follows: Fig.10 As shown, the slope of the linear function relationship is 0.0002.

[0112] Corresponding to step S302, the corresponding relationship between the mean value of the scratch modulus in each segmented data and the core depth is as follows: Fig.11 As shown, Fig.11 Core Depth is the core depth. is the scratch modulus, and the segmentation coefficient can be arbitrarily selected to be a more appropriate value, but it must satisfy that the segmentation coefficient is greater than the number of calibration samples, such as Fig.11 The core with a core depth of 0.3 meters in the figure has a segmentation coefficient of 15, so the first data is divided into 15 segments, each segmented data contains multiple scratch modulus data, and the mean value of all scratch moduli and in each segmented data is calculated as Fig.11 The vertical coordinate value, then according to the formula ;calculate Fig.11By using the horizontal coordinate value of , we can obtain the mean value of the scratch modulus of each segmented data and the point-to-point corresponding data of the core depth. By smoothly connecting these point-to-point data, we can obtain the continuous data of the core scratch modulus changing with the core depth. is the horizontal coordinate value corresponding to the i-th segment data, The length of each segmented data corresponding to the core depth after the core is divided. For example, for a core with a core depth of 0.3 meters, the segmentation coefficient is 15, and the length of each segmented data corresponding to the core depth is 0.02 meters. Of course, the above calculation of the horizontal coordinate value can also be other formulas, as long as it satisfies ≤ ≤ .

[0113] Since the linear functional relationship between the calibrated Young's modulus and the calibrated scratch modulus has been determined, the above Fig.11 The continuous data of the core scratch modulus changing with core depth can be multiplied by the slope 0.0002 to obtain Fig.12 The core Young's modulus data showing the core Young's modulus changing with core depth.

[0114] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0115] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for calculating the continuous Young's modulus of a core, characterized in that: The method for calculating the continuous Young's modulus of the core comprises: Using a tool to perform a scratch test experiment on the core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth; Sequentially sampling a plurality of calibration samples from the core along the core depth direction, determining a calibrated scratch modulus of each calibration sample according to the core depth of each calibration sample, a sampling position of each calibration sample on the core and the first data, and simultaneously performing an experiment on each calibration sample to determine a calibrated Young's modulus of each calibration sample; Determine a functional relationship between the calibrated scratch modulus and the calibrated Young's modulus according to the calibrated scratch modulus and the calibrated Young's modulus, and determine core continuous Young's modulus data of the core in which the Young's modulus of the core changes with the core depth according to the functional relationship and the first data; The step of using a tool to perform a scratch test experiment on the core along the core depth direction to determine first data of the scratch modulus of the core varying with the core depth comprises: Using a tool to perform a scratch test experiment on the core along the depth direction of the core to determine the original output data of the tangential force of the tool changing with the depth of the core; Performing slope calculation on the original output data to determine intermediate processed data of slope values ​​varying with core depth; Screening and calculating the intermediate processing data to determine first data of the scratch modulus of the core varying with the depth of the core; The step of determining the calibrated scratch modulus of each calibration sample according to the core depth on each calibration sample, the sampling position of each calibration sample on the core and the first data comprises: According to the core depth of the calibration sample and the sampling position of the calibration sample on the core, a corresponding portion of data is selected from the first data as a sample scratch modulus data set; Calculating the mean of all scratch modulus data in the sample scratch modulus data set to determine the calibrated scratch modulus; The mean value calculation formula is: ； in is the sum of all scratch modulus data in the sample scratch modulus data set corresponding to the i-th calibration sample, in units of ; Q—the number of scratch modulus data in the sample scratch modulus data set, dimensionless, is the calibrated scratch modulus of the ith calibration sample, in units of .

2. The method for calculating the continuous Young's modulus of a core according to claim 1, characterized in that: The steps of using a tool to perform a scratch test experiment on the core along the core depth direction to determine the original output data of the tangential force of the tool changing with the core depth include: Clamping and fixing the core; The tool starts to scrape the core from the core surface position along the direction of the core depth, and each time the scraping tool steps to a predetermined cutting depth in a direction perpendicular to the core depth direction, and each time the scraping angle and scraping speed of the tool are the same; Recording the tangential force variation data of the tool during the scraping process as the tangential force varies with the core depth; Select appropriate data from the tangential force change data as the original output data.

3. The method for calculating the continuous Young's modulus of a core according to claim 1, characterized in that: The steps of performing slope calculation on the original output data and determining the intermediate processed data whose slope value varies with the core depth include: Dividing the original output data into multiple segments of unit original output data; Performing slope calculation on each section of the unit original output data to determine the intermediate processed data; The slope value calculation formula is: ； is the slope value of the original output data of the i-th unit, in N / m; y B , y A is the first and last ordinate values ​​of the original output data of the i-th unit, in units of N. S i It is the length of the core depth corresponding to the original output data of the i-th unit, in meters.

4. The method for calculating the continuous Young's modulus of a core according to claim 1, characterized in that: The step of screening and calculating the intermediate processing data to determine the first data of the scratch modulus of the core varying with the core depth comprises: Screening out slopes with slopes greater than 0 in the intermediate processed data as valid slopes; Determine the corresponding relationship between the scratch modulus corresponding to each effective slope and the core depth according to the scratch modulus calculation formula according to the effective slope, tool width and cutting depth; The first data of the scratch modulus of the core varying with the core depth is determined according to the corresponding relationship between the scratch modulus corresponding to the effective slope and the core depth.

5. The method for calculating the continuous Young's modulus of a core according to claim 4, characterized in that: The scratch modulus calculation formula is: ； in, is the scratch modulus, in units of ; w is the tool width, in meters; d is the cutting depth, in meters; is the slope.

6. The method for calculating the continuous Young's modulus of a core according to any one of claims 1 to 5, characterized in that: The method for experimentally determining the calibration Young's modulus data of each calibration sample is a uniaxial triaxial compression test method.

7. The method for calculating the continuous Young's modulus of a core according to any one of claims 1 to 5, characterized in that: The step of determining the functional relationship between the calibrated scratch modulus and the calibrated Young's modulus comprises: A coordinate system is introduced, with the calibrated scratch modulus as the abscissa and the calibrated Young's modulus as the ordinate, and a linear fitting method is used to determine the linear function relationship between the calibrated Young's modulus and the calibrated scratch modulus.

8. The method for calculating the continuous Young's modulus of a core according to claim 7, characterized in that: The step of determining the core continuous Young's modulus data of the core according to the functional relationship and the first data, wherein the Young's modulus of the core varies with the core depth, comprises: Obtaining the slope of the linear function relationship; According to the length of the core depth, a suitable segmentation coefficient is selected to evenly segment the first data to obtain multiple segments of segmented data, and the corresponding relationship between the mean value of the scratch modulus in each segment of the segmented data and the core depth is determined; Determine the corresponding relationship data of the core Young's modulus and the core depth of each segmented data according to the determined corresponding relationship between the mean value of the scratch modulus in each segmented data and the core depth and the slope of the linear function relationship; The core continuous Young's modulus data is determined according to the corresponding relationship data between the core Young's modulus and the core depth of the segmented data of all segments.

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